Equation of Kim et al for Estimating Body Muscle Mass from Serum Creatinine and Cystatin C

NOTE: While the equation is designated muscle mass, it may represent fat- and bone-free body mass. The total body mass is described as a sum of fat, muscle and bone.

Patient selection: Korean adults age 25 to 84 years

Parameters:

(1) body weight in kilograms

(2) serum creatinine in mg/dL

(3) serum cystatin C in mg/L

(4) coefficient K

(5) sex

body muscle mass in kilograms =

= (body weight) * (creatinine) / ((K * (cystatin C) * (body weight)) + (creatinine))

Performance:

• The R^2 versus muscle mass by DXA was 0.83 in the derivation and 0.86 in validation cohorts.